Based on our in vitro studies of Raman spectroscopy for differentating normal and canceorus breast tissues, we have conducted a preliminary ex vivo study in a OR setting using the fiber optic based clinial Raman system. The has been conducted at the Department of Surgical Oncology at the Cleveland Clinic Foundation. The initial results suggest that good quality spectra of breast tissues can be obtained in a clinical setting. The spectra can be used to differentiate normal from cancerous tissues. In order to differentiate benign and malignant, an important clinical objective, high quality spectra are need to be collected without background intereference from optical fibers used to collect spectra. Future ex vivo studies will be conducted using new fiber optic probes which do not produce intense background signal.